The goals of the Center for Fetal Monkey Gene Transfer for Heart, Lung, and Blood Diseases are: (1) to provide accessible monkey models to the research community in which to evaluate the safety and efficiency of gene therapy strategies as they emerge;and (2) to provide NHLBI-funded investigators with essential expertise, resources, and services to actively pursue gene transfer approaches in monkeys in their research programs. The overriding objective of this renewal is to continue to fulfill our Center mission of providing essential services to investigators to explore crucial issues in gene delivery in a relevant preclinical nonhuman primate model. The success of our outreach program, research and service accomplishments, and support from the greater research community demonstrates the importance of this Center and the need for the services we provide to advance the field of gene therapy for the treatment of human disease. We have funded investigators annually through a competitive process and provided extensive services and training. We have also explored a series of basic questions in fetal gene delivery essential to the field. Our Objectives and Specific Aims for the next funding period include Objective 1, to focus on providing expertise and specialized services to NHLBI-funded investigators for the study of gene-based approaches in monkeys for the treatment of human disease. Specific Aim 1 addresses the Center administrative structure and dissemination of information, and Specific Aim 2 highlights the expertise, services, and resources we will provide to NHLBI-funded investigators who wish to evaluate their viral and non-viral gene transfer strategies in monkeys. In Objective 2, we will evaluate the efficiency and safety of recombinant viral vector systems (lentivirus, AAV) in transferring genes into fetal monkeys for the treatment of heart, lung, and blood diseases. These studies will be performed to expand our capabilities and provide more research opportunities for investigators. Specific Aim 1 focuses on correlative in vivo imaging techniques for monitoring gene expression long-term, and Specific Aim 2 focuses on methods to assess safety. The Center for Fetal Monkey Gene Transfer is unique in the ability to address essential questions in gene delivery in fetal, infant, and juvenile nonhuman primates, and has consistently provided investigators with extensive opportunities to advance the development of promising new therapies for the treatment of human diseases.